Implement showing CI bridge error messages

When a bridge job fails to create downstream pipeline,
we only show if it is failed or not.

With this, we will start showing failure reasons.

changelogs/unreleased/213666-display-bridge-failure-reason.yml

+---
+title: Implement showing CI bridge error messages
+merge_request: 29123
+author:
+type: other

lib/gitlab/ci/status/bridge/factory.rb

@@ -5,6 +5,10 @@ module Gitlab
     module Status
       module Bridge
         class Factory < Status::Factory
+          def self.extended_statuses
+            [Status::Bridge::Failed]
+          end
+
           def self.common_helpers
             Status::Bridge::Common
           end

lib/gitlab/ci/status/bridge/failed.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    module Status
+      module Bridge
+        class Failed < Status::Build::Failed
+        end
+      end
+    end
+  end
+end

spec/factories/ci/bridge.rb

@@ -7,7 +7,7 @@ FactoryBot.define do
     stage_idx { 0 }
     ref { 'master' }
     tag { false }
-    created_at { 'Di 29. Okt 09:50:00 CET 2013' }
+    created_at { '2013-10-29 09:50:00 CET' }
     status { :created }
     scheduling_type { 'stage' }
 
@@ -39,5 +39,19 @@ FactoryBot.define do
         )
       end
     end
+
+    trait :started do
+      started_at { '2013-10-29 09:51:28 CET' }
+    end
+
+    trait :finished do
+      started
+      finished_at { '2013-10-29 09:53:28 CET' }
+    end
+
+    trait :failed do
+      finished
+      status { 'failed' }
+    end
   end
 end

spec/lib/gitlab/ci/status/bridge/factory_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Ci::Status::Bridge::Factory do
+  let(:user) { create(:user) }
+  let(:project) { bridge.project }
+  let(:status) { factory.fabricate! }
+  let(:factory) { described_class.new(bridge, user) }
+
+  before do
+    stub_not_protect_default_branch
+
+    project.add_developer(user)
+  end
+
+  context 'when bridge is created' do
+    let(:bridge) { create(:ci_bridge) }
+
+    it 'matches correct core status' do
+      expect(factory.core_status).to be_a Gitlab::Ci::Status::Created
+    end
+
+    it 'fabricates status with correct details' do
+      expect(status.text).to eq s_('CiStatusText|created')
+      expect(status.icon).to eq 'status_created'
+      expect(status.favicon).to eq 'favicon_status_created'
+      expect(status.label).to be_nil
+      expect(status).not_to have_details
+      expect(status).not_to have_action
+    end
+  end
+
+  context 'when bridge is failed' do
+    let(:bridge) { create(:ci_bridge, :failed) }
+
+    it 'matches correct core status' do
+      expect(factory.core_status).to be_a Gitlab::Ci::Status::Failed
+    end
+
+    it 'matches correct extended statuses' do
+      expect(factory.extended_statuses)
+        .to eq [Gitlab::Ci::Status::Bridge::Failed]
+    end
+
+    it 'fabricates a failed bridge status' do
+      expect(status).to be_a Gitlab::Ci::Status::Bridge::Failed
+    end
+
+    it 'fabricates status with correct details' do
+      expect(status.text).to eq s_('CiStatusText|failed')
+      expect(status.icon).to eq 'status_failed'
+      expect(status.favicon).to eq 'favicon_status_failed'
+      expect(status.label).to be_nil
+      expect(status.status_tooltip).to eq "#{s_('CiStatusText|failed')} - (unknown failure)"
+      expect(status).not_to have_details
+      expect(status).not_to have_action
+    end
+
+    context 'failed with downstream_pipeline_creation_failed' do
+      before do
+        bridge.failure_reason = 'downstream_pipeline_creation_failed'
+      end
+
+      it 'fabricates correct status_tooltip' do
+        expect(status.status_tooltip).to eq(
+          "#{s_('CiStatusText|failed')} - (downstream pipeline can not be created)"
+        )
+      end
+    end
+  end
+end

spec/services/ci/create_cross_project_pipeline_service_spec.rb

@@ -475,5 +475,45 @@ describe Ci::CreateCrossProjectPipelineService, '#execute' do
         expect(bridge.failure_reason).to eq 'insufficient_bridge_permissions'
       end
     end
+
+    context 'when there is no such branch in downstream project' do
+      let(:trigger) do
+        {
+          trigger: {
+            project: downstream_project.full_path,
+            branch: 'invalid_branch'
+          }
+        }
+      end
+
+      it 'does not create a pipeline and drops the bridge' do
+        service.execute(bridge)
+
+        expect(bridge.reload).to be_failed
+        expect(bridge.failure_reason).to eq('downstream_pipeline_creation_failed')
+      end
+    end
+
+    context 'when downstream pipeline has a branch rule and does not satisfy' do
+      before do
+        stub_ci_pipeline_yaml_file(config)
+      end
+
+      let(:config) do
+        <<-EOY
+          hello:
+            script: echo world
+            only:
+              - invalid_branch
+        EOY
+      end
+
+      it 'does not create a pipeline and drops the bridge' do
+        service.execute(bridge)
+
+        expect(bridge.reload).to be_failed
+        expect(bridge.failure_reason).to eq('downstream_pipeline_creation_failed')
+      end
+    end
   end
 end